Fuel oil



Patented May 25, 1937.

UNITED STATES} PATENT OFFICE FUEL OIL ware -No Drawing.

11 Claims.

This invention relates to fuel oils and methods of preparing same or ofreducing the combustion residues of same.

When fuel oils are burned, a small amount of 5 carbonaceous residue orcoke results from the combustion. The formation of this residue is adisadvantage, for instance, in leading to the clogging of the burnersthrough which the fuel oil :is fed. As a result it makes necessary theshutl ting down of the burner occasionally to remove the residue and itmay also at more frequent intervals necessitate a readjustment of theburners in order to' compensate for the reduced amount of fuelpil beingfed through the burners.

1 It is an object of the present. invention to avoid these'and otherdifliculties by greatly reducing the amount of this carbonaceous residueor coke.

According to this invention, it has been found.

that the addition of a relatively small quantity of a 'high boiling.substance to a domestic fueloil results iii a decrease in the quantityof the carbonaceous residue formed during burning.

The fuel oils which may be treated in accord- 25 ance with thisinvention may have properties chlorinated or other derivatives thereof.

1 Average visg' Y cosity at 100 F.

- (Saybolt) Domest c light fuel oil 36 minimum; Less than 35. Domest cmedium fuel oil. 28minimum. About 35. Domestic heavy fuel oil.-. About24-26. About 41 or 42.

Light industrial fuel oil--- 18-22---.- 40-75.

45 The source of crude from which these oils may be derived is notmaterial. They may be so-- called native oils, '1. e., obtained by meredistillation from the original crude oil or else they may be obtained bycracking of a crude or some frac- 5 tion thereof. The original oil, fromwhich the heating oil is obtained, may be of paraflinic,

naphthenic or mixed type; the fuel oil may also no it is to be added(which is generally about 550 Application December 30, 1933, Serial No.704,786

to 600 F.). In other words, the addition agent should have a boilingpoint (or mid-boiling point between the approximate limits of 600 and700 or 750 F. It should also be a fraction having a Saybolt viscositybetween the approximate 5 limits of 40 and 500 seconds at 100 F. A widevariety of types of substances may be used as the addition agent, forinstance, high boiling mineral oils or organic compounds such asbydrocarbons, esters, alcohols, ketones, etc. or 10 This addition agent,also preferably has a relatively high solvent power (such as a kauributanol value above about or gum fluxing action (which means capable ofpreventing precipitation of 15 otheisubstances although not capable ofactually dissolving them' after. they are once precipitated); andbetween oils or other substances having equal characteristics in otherrespects it is preferable to use the one having the lower Conradsoncarbon. The kauri butanol test is described in circular 3'78 (February,1931) of the American Paint and Varnish Manufacturers -Association. Thenaphthenic type; of oils and other hydrocarbons described and claimed inco-pending application Ser. No. 658,153 of Sloane and Wasson, as well asthe high boiling esters and other oxygenated organic compounds describedand claimed in co-pending application Ser. No. 667,039 of Jones I.Wasson are suitable for use according to the present invention. Althoughthe addition agent should have a boiling point higher'than that of thefuel oil to which it is added still it should not be too high boiling ortoo viscous. For instance, the addition of 1% Q of a viscousPennsylvania cylinder stock to a fuel oil actually 'caused a slightincrease in the coke residue formed on combustion. If a petroleum oil isused as addition agent.-it is preferably an overhead product; in otherwords, it- 40 should. be obtained by distillation, although fractions ofsuitable gravity and viscosity may be separated from a crude or residualstock by extraction, fractional precipitation or in any other desiredmanner. I

The amount of the addition agent to be used is preferably between theapproximate limits of 0.5 and 1.5%. Satisfactory results have beenobtained with 0.75 and with 1.0%; although it'is obvious that lesser andgreater amounts, for instance, betweenthe approximate limits of 0.1 and5.0% may be used under certain circumstances. In general, the amount tobe used depends upon the type of the oil treated as well as the type ofaddition agent and the type of burner inv which the fuel oil is to beused. The invention has been found particularly applicable to fuel oilsto be used in the Timken and other types of rotary burners.

In carrying out the invention, the desired tional advantage of helpingto of addition agent, such as one of the high boiling oils or organiccompounds mentioned above,

is incorporated into the larger bulk of fuel oil with sufllcientagitation to insure thorough mixing. If desired, heat may be used tofacilitate thorough solution. This high boiling substance may be addedany time prior to actual burning. If added prior'to storage it maypresent the addistabilize the fuel oil during storage.

The valuable results obtained by the application of this inventioninclude primarily a reduction in the amount of carbonaceous or cokeresidue obtained upon combustion of the fuel oil, although in someinstances there is also an additional advantage in having a betterdistribution of the coke residue which is left. This latter feature isof more importance for range oils than it is for fuel oils to be used infurnaces. The reasons for the great reduction in the amount of car.-bonaceous residue and other advantages of the invention are not wellunderstood but it is believed that the presence of the small amount ofthe high boiling addition agent prevents the precipitation of the cokeor carbonaceous material which would otherwise tend to precipitate andhence it maintains a more: uniform or homogeneous solution longer and athigher temperatures than does the fuel oil alone. It thus facilitatescombustion of the entire mass.

The coking test which has been found satisfac Y tory for comparing theamount of carbonaceous be limited thereby, the following examples are.

given to illustrate the invention:

Addition agent (like vlw w B... are

. cc. oil

1. Fuel oil A 9i Ditto+l% Colombian pale nil 300 22 2. Fuel oil B- (endpt.=582 F.)... 228

Ditto+%% Colombian pale oil s00 108 3. Oil Iii-+51% Penna. Lube Dist. 4oiliagivg cyut (6805700; F.).fii] 1;;. 00 About 650- 38 oc a ecy nap1ene.--. 113 About 100 111 5. Oil B+9 octadecyl benz 58 About 650 92 0.Oil B+ methyl oleate About 520 184 7. Oil B+%% amyl stearate About 50About 000 55 The exact theory of operation of the invention is not wellunderstood and it is therefore desired that the invention should not belimited to any particular-theories nor to the examples which are hydrioalcohol.

given merely for the sake of illustration. In the appended claims it isintended to claim all inherent novelty in the invention as broadlyas theprior art permits. 1

We claim:

l. A fuel oil of less than 40 seconds viscosity Saybolt at 100 F.forming a high carbon residue, containing from 0.1 to 5.0% of an addedsoluble hydrocarbon, liquid at ordinary temperature, of

substantially higher boiling point than said fuel oil and also having akauributanol solvent power above about 15, said soluble hydrocarbonbeing capable of reducing the coke residue of the fuel oil.

2. A fuel oil composition according to claim 1 in which the addedsoluble hydrocarbon is a petro- .-leum distillate.

5. A fuel oil composition according to claim 3 in which the added liquidis a distillate of a naphthenic type petroleum oil.

6. A fuel oil composition according to claim 3 in which the added liquidhas a viscosity between 40 and 500 seconds Saybolt at 100 F.

7. A domestic fuel oil forming a high carbon residue, comprising a majorproportion of an oil having a Saybolt viscosity of less than about 45seconds at 100 F. and a distillation end point of about 550 to 600 F.,and about 0.75 to 1.0% of a pale oil having a mid-boiling point betweenthe approximate limits of 600 and 700 F.

8. The method of preparing a domestic fuel oil, which comprises addingabout 0.1% to 5.0% of a pale oil having a mid-boiling point between theapproximate limits of 600 and 700 F. to a fuel oil having a Sayboltviscosity of less than about 45 seconds at 100 F. and a distillation endpoint of about 550 to 600 F. whereby the amount of carbonaceous residueresulting from the combustion of the fuel oil is reduced.

9. The method of reducing the amount of, carbonaceous residue or cokeresulting from the combustionof a fuel oil of lessthan 40 secondsviscosity Saybolt at 100 E. which comprises adding thereto from 0.1% to5.0% of soluble hydrocarbon, liquid at ordinary temperatures, ofsumtantially higher boiling point'than said fuel oil and also compound.4

11. A fuel oil composition according to claim 3 in which the addedliquid is an ester of a mono- AMIOT P. HEWLE'I'I, CHARLES H. COLE.

